The nail unit in humans is a cutaneous structure located on the distal aspect of the digits of the upper and lower extremities. It is present on the dorsal surface and overlies the distal phalanx. Animals have related structure analagous to nails made up predominantly of keratin and known as hoofs, claws or talons. The nail plate constituting the cosmetic component of the nail unit is manufactured, in humans, predominantly by the nail matrix by a process of keratinization and condensation of specialized epithelial cells.
The nail plate, hereafter referred to simply the "nail" is, in the case of animals, in contact with the environment and therefore is subject to a variety of trauma. These include physical and chemical insults which have a deleterious effect, thus making it desirable to improve their flexibility, reverse brittleness and thickness, improve strength and obviate photo damage. It is also advantageous to improve the cosmetic appearance, particularly for humans, and animals produced for show purposes.
Nail units are also susceptible to a number of infections and diseases, cutaneous and/or systemic, which may require removal (evulsion). Thus, an agent capable of enhancing growth in such situations is greatly desired and would be helpful in general usage. Up to the present, no effective scientific modality exists for influencing the growth rates of nails in humans or reversing photodamage and the aging process. Consequently, the art seeks a method which will satisfy the above needs and which would provide a significant advance in the field of medicine, cosmetics, and veterinary science.